I’m sure by now you’ve heard the buzz around fasting — almost one in four Americans have tried it for dietary purposes, and at least four in five have at least heard the term. In fact, intermittent fasting was the most Googled food topic worldwide in 2019 and remains one of the biggest search queries online.
This surge of interest around fasting has attracted an enormous amount of attention. There are detractors against it, zealots for it, and curious people stuck in the middle — the latter of which gets blasted with information from both sides.
Fasting is a complex topic that undergoes continuous scientific research. Cutting through the clutter and noise takes some time, but from an applied research and scientific standpoint, you should know that fasting can have enormous benefits on your metabolic health.
Here’s how.
How fasting affects your metabolic health
Before we jump into the outcomes created by intermittent fasting, it may be helpful to understand the science behind it first.
The human body runs on two different fuels: glucose and ketones. Glucose is sugar that comes from food, while ketones are created by the liver when fat is broken down into energy.
When your body doesn’t receive a steady influx of glucose, it will switch to burning fat as an alternative energy source. We refer to this as entering ketosis, which takes around two to four days for the average adult.
You’ll remain in a fasted ketosis state for as long as you go without eating, and can prolong the window with the help of low-carb and low-sugar foods. Consuming high protein, high fat meals during your feeding window will encourage the efficient conversion of fatty acids, which prompts the body to remain in a healthier state.
There is a great deal of research pointing to the long-term effects of fasting on metabolic health.
Studies show that it may help you with:
- Feeling less hungry
- Losing more weight
- Boosting muscle growth
- Supporting heart health
Fasting also has the ability to positively affect many of your biometric markers. Research demonstrates that IF can reduce LDL cholesterol and triglycerides, boost testosterone, and encourage positive mood enhancement throughout the fasting period.
Most importantly, fasting can reduce your risk factors for heart disease, stroke, and other cardiovascular events — the main reason I recommend it to Stay Off My Operating Table®.
Safe practices for metabolic fasting
Done correctly, fasting will not put your body into ‘starvation mode,’ increase physical stress levels, or make it difficult to focus during the day. However, it’s still a dietary practice that should be approached with care, particularly if you are inexperienced or fall within a high risk category.
Here are some general principles that protect your metabolic health while fasting:
- Not everyone is a good candidate for fasting. Pregnant or breastfeeding women may want to find other ways of managing their weight. Additionally, people with kidney stones, gastroesophageal reflux, or diabetes may need special regimens. When in doubt, chat with your doctor or a metabolic health coach about your options.
- Many people jump headfirst into fasting without considering its long term effects — leading them to burn out from emotional exhaustion or pass out from a lack of fuel. To avoid this, you’ll want to start slowly and build up your fasting ‘muscles.’ Begin with a 12-hour fast to get comfortable with your body’s responses, then increase the duration as time goes on. Remember: fasting isn’t a contest. Take your time and only do what you can.
- Fasting is a process of abstaining from food — not from water. You should be drinking at least half your body weight in ounces during the day, and adding electrolytes like salt or lemon that will keep your muscles healthy. Coffee and tea are also acceptable fasting beverages, although remember that too much coffee could make you dehydrated. Don’t attempt a dry fast without consulting with healthcare experts.
If at any time you feel uncomfortable or uneasy about your fast, or if you want the guidance of an expert by your side, don’t hesitate to reach out to a metabolic health coach or your PCP.
How long should you fast?
Studies have found that prolonged fasts – 48 hours or more – can help with cell repair and regeneration, which has notable health benefits.
This can be an intimidating prospect for a lot of people, and if your goal is to fast to curb hunger pangs, blood sugar levels, or your weight, prolonged fasts aren’t necessary.
Instead, you could look at intermittent fasting instead. This simply involves having a longer period during the day without eating. The most common approach is 16:8, which simply means having an eight-hour feeding window each day, and 16 hours of not eating. The 16 hours includes sleeping, so for example if you had dinner at 8pm your fasting window would last until midday the following day.
Simply skipping breakfast will mean you’re fasting, and this is one of the most popular methods. Alternatively, depending on your routines, you may prefer to make lunch the last meal of the day and skip an evening dinner. There are no set rules other than the fasting window needs to be continuous – if you eat breakfast and dinner, then skipping lunch doesn’t qualify as fasting.
How to get started with metabolic fasting
Fasting isn’t hard in a technical sense, but it can feel tricky to navigate without prior experience or outside support, particularly prolonged fasts. Picking the right exercise regimen may require some pre-planning depending on your pattern, and abstaining from bedtime snacks and regular mealtimes (especially when loved ones eat in front of you) can be difficult at first.
With the right support and guidance, fasting for metabolic health can be a lifestyle modification that provides benefits well into the future.
If you’d like to learn more about fasting, ketosis, and how to listen to your body, you’re welcome to sign up for my Introduction to Fasting course. I’ll explain how to get started, explain some of the benefits, and outline the startup phases in greater detail.